• Proceedings of the KSR Conference
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• 2002.10a
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• pp.434-439
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• 2002

The researches on the direct drive system, which directly transfers axle load of the traction motor to wheels, have been developed as a next generation drive system in Japan and Europe. As a result of excluding couplings and gear units, the direct drive system has advantages on the bogie mount space to be smaller sized, lower noisy, more efficient and less weighted than the conventional drive system - indirect drive system. Since the simplification of the direct drive system design depends on the design of the traction motors, the researches on the direct drive system with focusing on the traction motors get started. The advantages/disadvantages of direct drive system, types, structures, cooling systems and interfaces of the traction motors are presented on this paper. Furthermore, the development of other countries on the electric equipments of the next generation railway vehicles are discussed and the necessity ＆ requirement for developing new concepts of traction motors are assured.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.87-93
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• 2002

This paper is presented new fuzzy controller for high performance of induction motor drive. New fuzzy controller took out appropriate amounts of accumulated control input according to fuzzy described situations in addition to the incremental control input calculated by conventional direct fuzzy controller. The structures of the proposed controller was motivated by the problems of direct fuzzy controller. The direct controller was given generally inevitable overshoot when one tries to reduce rise time of response. The undesirable characteristics of the direct fuzzy controller are caused by integrating operation of the controller, even though the integrator itself is introduced to overcome steady state error in provide a thorough comparative insight into the behavior of induction motor drive with direct and new fuzzy speed controller. The validity of the comparative results is confirmed by the simulation results for induction motor drive system.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2057-2061
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• 2015

This paper describes analysis and experimental characterization of low speed direct drive fractional slot concentrated winding (FSCW) surface permanent magnet synchronous motor (SPMSM) with consequent pole (CP) rotor, for which studies have been recently performed. The proposed motor, which consists of 30 poles and 36 slots, is analyzed and characterized by extensive 2D finite element analysis (FEA) and together with 3D FEA for an appropriate PM overhang length design. The validity of the analysis is confirmed by the corresponding experiments which fully characterize the proposed motor with excellent agreement between the FEA and the experiments. Thermal stability is also experimentally examined to determine continuous operating points and instantaneous operating points of the proposed motor. It is highly expected that the proposed motor is applicable for low speed direct drive applications.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.69-71
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• 1997

The direct drive motor is directly coupled by load. So, it is directly affected by load and disturbances. To control the direct drive motor, a robust controller is need. The main feature of variable structure system is that system trajectories are robust and insensitive to parameter variations and disturbances in the sliding mode. In this paper, adaptive variable structure controller, is used for the BLDD SM(Brushless Direct Drive Servo Motor) control. The chattering problem is reduced by using the saturation function.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.148-154
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• 2014

This paper describes problems of the sensorless starting of horizontal axis washing machines with direct drive and suggests solution, which was experimentally verified. Horizontal axis washing machines have very difficult conditions for the drive starting, especially at full load. Inertia of the tub and water, torque from the laundry make load torque at starting higher than rated one and sometimes even higher than the maximum torque of the motor, which makes sensorless starting extremely challenging task. This paper suggests modified open-loop starting, where control system is closed shortly after beginning at low speed and rotates the drum until laundry restructuring. To ensure proper work of the sensorless algorithm at low speed additional measures for increasing of the estimation algorithm performance have been taken. These measures include special algorithm for the drive parameters estimation, which has been developed and verified by the experimental results.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.688-694
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• 2009

As a drive system for next generation train, we have been making research and development of a direct drive traction motor system without the conventional reduction gear. This traction motor is expected to have many advantages such as low noise, reduced maintenance, and energy saving. Due to the demand for high-output motors in the limited space between the wheels, open-ventilating traction motors with gear box have been widely used for many years. However, a conventional open-ventilating traction motor is necessary periodical disassembly to remove the accumulated dust from open-air ventilation. Reducing this burden, as well as increasing energy efficiency and reducing noise, would benefit the next generation of traction motors. To address these needs, KRRI have been developing a fully enclosed type direct drive motor(DDM) with high-efficiency permanent magnet for the next generation train.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1391-1396
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• 2009

The direct drive motor used in a precision motion rotate at about 1/10 speed and high torque comparing with general rotary motor. Excessive heating of the coils cause an exacerbating the heat problems and reducing the performance of motor. Because the rotation speed of the rotor and surrounding air is low, the motor can not be inefficiently cooled, the thermal analysis in the motor is very important. As the variations of rotation speed and torque, the temperature of several parts is measured and the features of the heat transfer is analyzed and improved.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.224-227
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• 2002

This paper is proposed new fuzzy controller for speed control of induction motor drive. New fuzzy controller take out appropriate amounts of accumulated control input according to fuzzily described situations in addition to the incremental control input calculated by conventional direct fuzzy controller. The structures of the proposed controller is motivated by the problems of direct fuzzy controller. Proposed controller fuzzily clear out integrated quantifies according to situation. This paper attempts to provide a thorough comparative insight into the behavior of induction motor drive with direct and new fuzzy speed controller. The validity of the comparative results is confirmed by simulation results for induction motor drive system.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1860-1865
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• 2008

The propulsion for locomotive application has changed from the DC motor system to the induction motor system. Although the induction motor system has almost reached the stage of maturity, this system also needs to be changed to the PM motor system for the direct drive without using reduction gear. Thus, the IPMSM(Interior buried Permanent Magnet Synchronous Motor) has been adopted to meet the locomotive driving specification. In this paper, the design of IPMSM satisfying driving specifications for the direct drive has been performed using the advanced F.E.M.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.304-315
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• 2013

In this paper, analysis of cascaded H-bridge multilevel inverter in DTC-SVM (Direct Torque Control-Space Vector Modulation) based induction motor drive for FCEV (Fuel Cell Electric Vehicle) is presented. Cascaded H-bridge multilevel inverter uses multiple series units of H-bridge power cells to achieve medium-voltage operation and low harmonic distortion. In FCEV, a fuel cell stack is used as the major source of electric power moreover the battery and/or ultra-capacitor is used to assist the fuel cell. These sources are suitable for utilizing in cascaded H-bridge multilevel inverter. The drive control strategy is based on DTC-SVM technique. In this scheme, first, stator voltage vector is calculated and then realized by SVM method. Contribution of multilevel inverter to the DTC-SVM scheme is led to achieve high performance motor drive. Simulations are carried out in Matlab-Simulink. Five-level and nine-level inverters are applied in 3hp FCEV induction motor drive for analysis the multilevel inverter. Each H-bridge is implemented using one fuel cell and battery. Good dynamic control and low ripple in the torque and the flux as well as distortion decrease in voltage and current profiles, demonstrate the great performance of multilevel inverter in DTC-SVM induction motor drive for vehicle application.